Digital Echo Glossary

Application Profile - is a subset of the DICOM Standards which explicitly prescribes the content and format of storing medical images onto physical transportable media. It is specific for each imaging modality and categories of image matrix size or system capabilities.

CD-R - is an acronym which stands for Compact Disc-Recordable. This form of CD media allows user defined data to be recorded onto the disc. It is different from audio CD's and other forms of CD-ROM's which are typically mass-produced from a master disc.

CD-ROM - is an acronym which stands for Compact Disc-Read Only Memory. The digital information on the disc is created by mass production pressing techniques.

Compression - is a general description for a family of mathematical techniques which can reduce the amount of data and therefore improve digital storage efficiency and retrieval rates.

Conformance Statement - is a document provided by manufacturers of DICOM compatible equipment which identifies the subset(s) of the DICOM standards which individual products actually support.

DICOM - is an acronym which stands for Digital Image and Communications in Medicine.

Interchange - generally refers to the exchange of diagnostic imaging studies between institutions. Sometimes it is also used in the context of exchange within an institution.

JPEG-DCT - is an acronym which stands for Joint Photographic Experts Group - Discrete Cosine Transform. It is the lossy compression algorithm used to store Echocardiograms in DICOM.

JPEG-DPCM - is an acronym which stands for Joint Photographic Experts Group - Differential Pulse Code Modulation. It is the lossless compression algorithm used to store X-ray Angiograms in DICOM.

Lossless Compression - is a category of digital image compression types which possess the following characteristics.

° The original digital images can be exactly (bit for bit) reproduced as originally acquired.
° It does not affect post-decompression digital image processing.
° It can achieve only relatively low levels of data reduction.

Lossy Compression - is a category of digital image compression types which possess the following characteristics.

° The original digital images can not be exactly reproduced as orginally acquired, but the changes may be visually inapparent.
° The compression algorithms can introduce artifacts into the images and affect post-decompression digital image processing.
° The prevalence of artifacts increases as the amount of compression increases or as the image detail content increas
° Much higher degrees of compression are possible than with lossless compression. es.

MEDICOM - is the legal name for the DICOM standard within the European Union as accepted by CEN TC 251

NEMA - is an acronym which stands for National Electrical Manufacturers Association.

TC 251 - stands for Technical Committee #251 of CEN